Singulating sheet feeder

ABSTRACT

A singulating sheet feeder includes a deck for slidably supporting a plurality of sheets and a drive system for moving the sheets along the deck. The drive system includes a drive element for engaging a lowermost sheet to move the sheets into a shingled arrangement. The sheet feeder further includes a transport element for transporting the lowermost sheet away from the plurality of sheets and a separator element proximate to the transport element including a substantially planar surface for engaging leading edges of subsequent sheets to retard motion of the subsequent sheets as the lowermost sheet is transported, wherein the substantially planar surface is disposed at an acute angle to the deck.

FIELD OF THE INVENTION

The present invention relates to a sheet feeder and, more particularly,to a sheet feeder for singulating sheets.

BACKGROUND OF THE INVENTION

Inserter systems are used to create mailpieces for a range ofapplications. Inserters receive paper in a feeder, then utilize agenerally modular array of components to carry out the various processesassociated with mailpiece creation. The processes include preparingdocuments, assembling the documents associated with a given mailpiece,adding any designated inserts, stuffing the assembly into an envelope,and printing information on the envelope.

Some inserter systems utilize web feeders, in which paper is providedfrom a roll or a fan-fold stack for processing to form documents. Suchdocuments may comprise utility bills or financial statements, forexample. Other systems utilize cut-sheet type feeders, in which a stackof individual sheets is provided to the system for processing.

A significant consideration for cut-sheet feeders is the ability toreliably deliver documents for processing, while protecting thepreprinted information on the documents. Some conventional cut-sheetfeeders have been found to damage documents during the feeding process.In some cases, documents printed on sensitive grades of paper have beenscuffed or scratched. In other cases, documents printed using certaintoners have had the printed content smudged or transferred to otherdocuments.

SUMMARY OF EXEMPLARY ASPECTS

In the following description, certain aspects and embodiments of thepresent invention will become evident. It should be understood that theinvention, in its broadest sense, could be practiced without having oneor more features of these aspects and embodiments. It should also beunderstood that these aspects and embodiments are merely exemplary.

To overcome the drawbacks of the prior art and in accordance with thepurpose of the invention, as embodied and broadly described herein, oneaspect of the invention relates to a singulating sheet feeder comprisinga deck for slidably supporting a plurality of sheets and a drive systemfor moving the sheets along the deck. The drive system may comprise adrive element for engaging a lowermost sheet to move the sheets into ashingled arrangement. The sheet feeder may further comprise a transportelement for transporting the lowermost sheet away from the plurality ofsheets and a separator element proximate to the transport elementcomprising a substantially planar surface for engaging leading edges ofsubsequent sheets to retard motion of the subsequent sheets as thelowermost sheet is transported, wherein the substantially planar surfaceis disposed at an acute angle to the deck.

In another aspect, the invention relates to a method of singulatingsheets comprising slidably supporting a plurality of sheets on a deckand moving the sheets along the deck. In one embodiment, moving thesheets comprises engaging a lowermost sheet to move the sheets into ashingled arrangement. The method may further comprise transporting thelowermost sheet away from the plurality of sheets using a transportelement, and engaging leading edges of subsequent sheets with asubstantially planar surface of a separator element proximate to thetransport element to retard motion of the subsequent sheets as thelowermost sheet is transported, wherein the substantially planar surfaceis disposed at an acute angle to the deck.

Aside from the structural and procedural arrangements set forth above,the invention could include a number of other arrangements, such asthose explained hereinafter. It is to be understood that both theforegoing description and the following description are exemplary only.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate exemplary embodiments of theinvention and, together with the description, serve to explain theprinciples of the invention. In the drawings,

FIG. 1 is a schematic view of an inserter system utilizing an embodimentof the singulating sheet feeder of the present invention;

FIG. 2 is a side view of a portion of an embodiment of the singulatingsheet feeder of the present invention; and

FIG. 3 is a detail view of the sheet feeder shown in FIG. 2.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Reference will now be made in detail to exemplary embodiments of theinvention, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers will be usedthroughout the drawings to refer to the same or like parts.

Embodiments of the singulating sheet feeder according the invention willbe described with reference to certain applications in mailpieceinserter systems. It should be understood, however, that the device ofthe invention may be used in association with other systems configuredto handle and transport sheets.

A schematic view of an inserter system 10 incorporating the singulatingsheet feeder 12 of the invention is shown in FIG. 1. The illustratedexemplary inserter system 10 comprises the sheet feeder 12, whichprovides preprinted documents for processing. The documents, which maycomprise bills or financial statements, for example, are provided by thesheet feeder 12 as individual cut sheets.

The documents next move to an accumulator 14, where the documents forrespective mailpieces are assembled and folded. The folded accumulationsnext move to a buffer 16, which holds the accumulations for sequentialprocessing. The accumulations next move to a chassis 18. As eachaccumulation moves through the chassis 18, inserts from a plurality offeeder modules 20 are added to the accumulation.

The accumulations next enter an insertion area 22, where the finishedaccumulations are stuffed into envelopes provided by an envelope hopper24, and the envelopes are sealed. The stuffed, sealed envelopes nextpass through a transport system 26, which may invert the accumulationsor maintain their orientation, depending on the application.

The envelopes then enter a printing area 28, where markings, such as apostage indicia and/or address information, for example, are appliedusing a printer 30. Finally, the completed mailpieces are deposited on aconveyor 32.

An embodiment of the singulating sheet feeder 12 will be described withreference to FIG. 2.

As discussed above, in some inserter systems the sheet feeder isarranged as the first module of a modular system. Accordingly, the sheetfeeder 12 comprises a deck 34 for slidably supporting a plurality ofsheets. The sheets comprise the preprinted documents that will form themailpieces produced by the inserter system. Thus, the sheets maycomprise statements, such as billing statements or banking statements,for example, or any other type of reports or information.

Inserter systems are capable of producing a large number of mailpiecesin a given production run due to high processing speeds. Accordingly, alarge group of sheets, which will form the mailpieces, may be placed onthe deck at the beginning of a run.

The sheet feeder 12 further comprises a drive system 36 for moving thesheets along the deck 34. The drive system 36 may comprise multiplestages for moving the sheets in a controlled manner. For example, thedrive system 36 may comprise an upstream portion, configured to move thebulk of the sheets in a continuous mode, and a downstream portion,configured to move a subset of the sheets sequentially.

In some embodiments, the drive system 36 comprises a drive element 38for engaging a lowermost sheet to move the sheets into a shingledarrangement. In the embodiment shown in FIG. 2, the drive element 38comprises a belt. In one example, the belt may comprise rubber oranother material having a relatively high coefficient of friction forengaging the sheets for movement. Other types of drive elements may alsobe used. In addition, one or more drive elements may be used.

As the sheets are moved into the shingled arrangement, the sheets in thegroup begin to spread out in the direction of the transport path P, withthe lower sheets in the group moving forward to be processed first. Thelowermost sheet is the lead sheet and is processed first.

The sheet feeder 12 further comprises a transport element 40 fortransporting the lowermost sheet away from the plurality of sheets. Inthe illustrated embodiment, the transport element 40 comprises aselectively rotatable roller. The roller in some embodiments is providedwith a coating having relatively high coefficient of friction forengaging the sheets for movement. Other transport elements may also beused. In one embodiment, the drive element 38 and the transport element40 are driven simultaneously to ensure precise transport of thelowermost sheet for downstream processing.

The sheet feeder 12 further comprises a separator element 42 proximateto the transport element 40. The separator element 42 comprises asubstantially planar surface 44 for engaging leading edges of subsequentsheets to retard motion of the subsequent sheets as the lowermost sheetis transported. In the illustrated embodiment, the separator element 42is stationary during the transport of sheets.

As shown in FIG. 2, the substantially planar surface 44 of the separatorelement 42 is disposed at an acute angle A to the deck 34. In oneembodiment, the angle A ranges from approximately 50 degrees toapproximately 70 degrees. In another embodiment, the angle A isapproximately 60 degrees.

Unexpectedly, the separator element according to the invention does notutilize a surface having a high coefficient of friction, such as thatprovided by coatings or surface roughness, as in conventional devices.Rather, experimentation and testing have shown that superior results maybe achieved in sheet singulation using a separator element havingcertain geometric features described herein. Due to the geometricfeatures incorporated in the device of the invention, there is no needfor the substantially planar surface 44 of the separator element to havea high coefficient of friction to assist in retarding the pieces to beheld.

In one embodiment, the substantially planar surface 44 has an averagesurface roughness of approximately 10 microns or less. In one example, aseparator element 42 was made from 2024 aluminum having a machinedfinish. In another example, the 2024 aluminum was coated with a nickelalloy to prevent premature wear due to the abrasive nature ofparticulate matter used in the paper-making process. Other alloys orother non-metallic compositions having a relatively low coefficient offriction may also be used.

In the illustrated embodiment, the planar surface 44 of the separatorelement 42 is disposed upstream of a contact point C between thetransport element 40 and the lowermost sheet. In one example, thedownstream edge 46 of the planar surface 44 is disposed 3 mm upstream ofthe contact point C. In other embodiments, the downstream edge 46 islocated approximately at contact point C or downstream of contact pointC.

In some embodiments, the separator element 42 according to the inventioncomprises a polygonal prism defining multiple substantially planarsurfaces. In the embodiment shown in FIG. 2, the separator element 42comprises a triangular prism mounted on a shaft 48. Other polygonalprisms may also be used.

In the illustrated embodiment, the separator element is selectivelypivotable, as indicated by the curved arrow, to dispose a desired one ofthe multiple substantially planar surfaces at an acute angle to the deck34. In such an arrangement, when a given surface has become worn ordamaged, the separator element may be pivoted about its center 49 topresent a new surface for subsequent use.

As shown in FIG. 2, the separator element 42 defines a gap G withrespect to the transport element 40 in a direction perpendicular to thedeck 34. In some embodiments, the gap has a height at least as large asa thickness of a sheet. In one example, the gap G is approximately equalto the thickness of a sheet. The gap G may also be greater than or lessthan the thickness of a sheet, depending on certain material propertiesof the sheets.

The shaft 48 illustrated in FIG. 2 forms a portion of an adjustmentmechanism 50, supported by the device housing (not shown), for example,that allows a user to vary the size of the gap G, as well as theposition of the separator element 42 along the transport path P.

In one embodiment, the sheet feeder 12 further comprises a take-awaytransport element 52 downstream of the transport element 40. Thetake-away transport element 52 comprises a driven roller 54 and anopposing follower roller 56 in the illustrated embodiment. In oneembodiment, the take-away transport element 52 is driven simultaneouslywith the drive element 38 and the transport element 40 to ensure precisetransport of the lowermost sheet for downstream processing.

In operation, a group of preprinted sheets are placed on the deck 34 ofthe sheet feeder 12. The drive system 36 is activated to move the sheetsalong the deck 34. The drive element 38 engages the lowermost sheet ofthe group and moves the sheets into a shingled arrangement.

In one example, the separator element 42 is adjusted so that the gap Gwith respect to the transport element 40 is slightly greater than thethickness of the sheets in the group being processed. In one example,the gap G is set to approximately 1.5 times the thickness of the sheets.As discussed above, other gap sizes may also be used.

As the sheets proceed along the deck 34, as shown in FIG. 3, thelowermost sheet 58 passes between the transport element 40 and theseparator element 42 through the gap G, while the leading edges of thesubsequent sheets 60-66 engage the substantially planar surface 44 ofthe separator element 42.

The action of the subsequent sheets 60-66 against the planar surface 44creates a force on the lowermost sheet 58, which acts through the nextsubsequent sheet 60, i.e., the sheet adjacent to the lowermost sheet 58.That force creates a normal force between the transport element 40 andthe lowermost sheet 58 that allows the transport element 40 to engagethe lowermost sheet 58 and transport that sheet away from the group ofsheets.

The angle of presentation of the planar surface 44 of the separatorelement 42, resulting from the acute angle A, the gap G, and therelative position along the transport path P, may mitigate the excessiveforces generated by a wedging effect encountered in some conventionaldevices, where the subsequent sheets are compressed into a narrow spaceas the sheets are advanced.

The lowermost sheet 58 is then engaged by the take-away transportelement 52, shown in FIG. 2, and transported for downstream processing.

The next subsequent sheet 60 then becomes the lowermost sheet and theprocess continues until all of the shingled sheets have been transportedfor downstream processing.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the structure andmethodology described herein. Thus, it should be understood that theinvention is not limited to the examples discussed in the specification.Rather, the present invention is intended to cover modifications andvariations.

1. A singulating sheet feeder, comprising: a deck for slidablysupporting a plurality of sheets; a drive system for moving the sheetsalong the deck, the drive system comprising a drive element for engaginga lowermost sheet to move the sheets into a shingled arrangement; atransport element for transporting the lowermost sheet away from theplurality of sheets; and a separator element proximate to the transportelement comprising a substantially planar surface for engaging leadingedges of subsequent sheets to retard motion of the subsequent sheets asthe lowermost sheet is transported, wherein the substantially planarsurface is disposed at an acute angle to the deck.
 2. The sheet feederof claim 1, wherein the transport element comprises a selectivelyrotatable roller.
 3. The sheet feeder of claim 1, wherein the acuteangle ranges from approximately 50 degrees to approximately 70 degrees.4. The sheet feeder of claim 3, wherein the acute angle is approximately60 degrees.
 5. The sheet feeder of claim 1, wherein the substantiallyplanar surface has an average surface roughness of approximately 10microns or less.
 6. The sheet feeder of claim 1, wherein thesubstantially planar surface is disposed proximate to a contact pointbetween the feeding element and the lowermost sheet.
 7. The sheet feederof claim 1, wherein the separator element comprises a polygonal prismdefining multiple substantially planar surfaces.
 8. The sheet feeder ofclaim 7, wherein the separator element is selectively pivotable todispose a desired one of the multiple substantially planar surfaces atan acute angle to the deck.
 9. The sheet feeder of claim 1, wherein theseparator element defines a gap with respect to the feeding element in adirection perpendicular to the deck.
 10. The sheet feeder of claim 9,wherein the gap has a height approximately as large as a thickness of asheet.
 11. The sheet feeder of claim 9, wherein the separator element isadjustably mounted to allow the gap to be varied.
 12. A method ofsingulating sheets, comprising: slidably supporting a plurality ofsheets on a deck; moving the sheets along the deck, wherein movingcomprises engaging a lowermost sheet to move the sheets into a shingledarrangement; transporting the lowermost sheet away from the plurality ofsheets using a transport element; and engaging leading edges ofsubsequent sheets with a substantially planar surface of a separatorelement proximate to the transport element to retard motion of thesubsequent sheets as the lowermost sheet is transported, wherein thesubstantially planar surface is disposed at an acute angle to the deck.13. The method of claim 12, wherein the transport element comprises aselectively rotatable roller.
 14. The method of claim 12, wherein theacute angle ranges from approximately 50 degrees to approximately 70degrees.
 15. The method of claim 14, wherein the acute angle isapproximately 60 degrees.
 16. The method of claim 12, wherein thesubstantially planar surface has an average surface roughness ofapproximately 10 microns or less.
 17. The method of claim 12, whereinthe substantially planar surface is disposed proximate to a contactpoint between the feeding element and the lowermost sheet.
 18. Themethod of claim 12, wherein the separator element comprises a polygonalprism defining multiple substantially planar surfaces.
 19. The method ofclaim 18, further comprising selectively pivoting the separator elementto dispose a desired one of the multiple substantially planar surfacesat an acute angle to the deck.
 20. The method of claim 12, wherein theseparator element defines a gap with respect to the feeding element in adirection perpendicular to the deck.
 21. The method of claim 20, whereinthe gap has a height approximately as large as a thickness of a sheet.22. The method of claim 20, further comprising adjusting a position ofthe separator element to vary the gap.